#region Licence
// Copyright (c) 2008 James Gregory (james@jagregory.com)
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// 
//     * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//     * Neither the name of James Gregory nor the names of its
//     contributors may be used to endorse or promote products derived from this
//     software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion

using System.Collections.Generic;
using System.IO;
using Boo.Lang.Compiler;
using Boo.Lang.Compiler.Ast;
using Boo.Lang.Compiler.IO;
using Boo.Lang.Compiler.Pipelines;
using Boo.Lang.Compiler.TypeSystem;
using JAGregory.BooPlugin.Language.Members;

namespace JAGregory.BooPlugin.Language
{
    public class SourceInterrogator
    {
        private readonly BooCompiler compiler = new BooCompiler();
        private readonly MemberLookupVisitor visitor = new MemberLookupVisitor();

        public SourceInterrogator()
        {
            compiler.Parameters.OutputWriter = new StringWriter();
            compiler.Parameters.Pipeline = new ResolveExpressions();
            compiler.Parameters.Pipeline.BreakOnErrors = false;
            compiler.Parameters.Pipeline.Add(visitor);
        }

        private void Compile(string filename, string source)
        {
            compiler.Parameters.Input.Add(new StringInput(filename, source));
            compiler.Run();
        }

        public MemberDeclarationCollection GetRelevantMembers(string filename, string source, int line, int column, int offset)
        {
            visitor.Line = line;
            visitor.Column = column;
            
            return MemberSelect(filename, source.Remove(offset, 1));
        }

        private MemberDeclarationCollection MemberSelect(string filename, string source)
        {
            Compile(filename, source);

            MemberDeclarationCollection collection = new MemberDeclarationCollection();
            collection.AddRange(GetMembersInEntity(visitor.Target));
            return collection;
        }

        private List<MemberDeclaration> GetMembersInEntity(Node node)
        {
            List<MemberDeclaration> members = new List<MemberDeclaration>();

            IEntity entityFromNode = TypeSystemServices.GetEntity(node);
            INamespace namespaceEntity = entityFromNode as INamespace;

            if (namespaceEntity == null && entityFromNode is InternalLocal)
                namespaceEntity = ((InternalLocal)entityFromNode).Type;

            IEntity[] entities = TypeSystemServices.GetAllMembers(namespaceEntity);

            // this needs some serious cleaning up...
            // it iterates the returned entities (which'll contain everything, public, private, static, special etc...)
            // then it tries to guess what to show. Problem is determining context, as currently using
            // a Type shows instance members too - needs some polymorph methinks.

            // could maybe cast as IAccessibleMember to determine whether to show, then cast to IEntityWithParameters
            // to do overloads
            foreach (IEntity entity in entities)
            {
                MemberDeclaration member = MemberDeclaration.FromEntity(entity);

                switch (entity.EntityType)
                {
                    case EntityType.Field:
                    case EntityType.Property:
                        IAccessibleMember accessibleMember = (IAccessibleMember)entity;

                        if (!accessibleMember.IsPublic)
                            member = null;

                        break;
                    case EntityType.Method:
                    case EntityType.BuiltinFunction:
                        IMethod method = (IMethod)entity;

                        if (!method.IsSpecialName && method.IsPublic)
                            member.Signatures.Add(GetSignatures(method));
                        else
                            member = null;
                        
                        break;
                    case EntityType.Constructor:
                        IConstructor constructor = (IConstructor)entity;

                        if (constructor.IsPublic)
                            member.Signatures.Add(GetSignatures(constructor));
                        else
                            member = null;

                        break;
                }

                if (member != null)
                    members.Add(member);
            }

            return members;
        }

        private MemberSignature GetSignatures(IEntityWithParameters method)
        {
            MemberSignature signature = new MemberSignature();

            foreach (IParameter parameter in method.GetParameters())
            {
                signature.Parameters.Add(string.Format("{0} as {1}", parameter.Name, parameter.Type));
            }

            return signature;
        }
    }
}